使用bm算法进行字符串匹配的例子.

 

使用bm算法进行字符串匹配的例子.

// BM.cpp : Defines the entry point for the console application.//#include <stdio.h>#include <string>#define XSIZE 256#define ASIZE 256#define MAX(x,y) (x) > (y)? (x):(y)#define OUTPUT(x) printf("匹配位置:%d/n",x)#define PatternStr "付"#define MainStr "AAAAa付付b付"void preBmBc(char *x, int m, int bmBc[]) {int i;for (i = 0; i < ASIZE; ++i)bmBc[i] = m;for (i = 0; i < m - 1; ++i)bmBc[x[i]] = m - i - 1;}void suffixes(char *x, int m, int *suff) {int f, g, i;suff[m - 1] = m;g = m - 1;for (i = m - 2; i >= 0; --i) {if (i > g && suff[i + m - 1 - f] < i - g)suff[i] = suff[i + m - 1 - f];else {if (i < g)g = i;f = i;while (g >= 0 && x[g] == x[g + m - 1 - f])--g;suff[i] = f - g;}}}void preBmGs(char *x, int m, int bmGs[]) {int i, j, suff[XSIZE];suffixes(x, m, suff);for (i = 0; i < m; ++i)bmGs[i] = m;j = 0;for (i = m - 1; i >= 0; --i)if (suff[i] == i + 1)for (; j < m - 1 - i; ++j)if (bmGs[j] == m)bmGs[j] = m - 1 - i;for (i = 0; i <= m - 2; ++i)bmGs[m - 1 - suff[i]] = m - 1 - i;}void BM(char *x, int m, char *y, int n) {int i, j, bmGs[XSIZE], bmBc[ASIZE];/* Preprocessing */preBmGs(x, m, bmGs);preBmBc(x, m, bmBc);/* Searching */j = 0;while (j <= n - m) {for (i = m - 1; i >= 0 && x[i] == y[i + j]; --i);if (i < 0) {OUTPUT(j);j += bmGs[0];}elsej += MAX(bmGs[i], bmBc[y[i + j]] - m + 1 + i);}}int main(int argc, char* argv[]){BM(PatternStr,strlen(PatternStr),MainStr,strlen(MainStr)); getchar(); return 0;}// BM.cpp : Defines the entry point for the console application.//#include <stdio.h>#include <string>#define XSIZE 256#define ASIZE 256#define MAX(x,y) (x) > (y)? (x):(y)#define OUTPUT(x) printf("匹配位置:%d/n",x)#define PatternStr "付"#define MainStr "AAAAa付付b付"void preBmBc(char *x, int m, int bmBc[]) {int i;for (i = 0; i < ASIZE; ++i)bmBc[i] = m;for (i = 0; i < m - 1; ++i)bmBc[x[i]] = m - i - 1;}void suffixes(char *x, int m, int *suff) {int f, g, i;suff[m - 1] = m;g = m - 1;for (i = m - 2; i >= 0; --i) {if (i > g && suff[i + m - 1 - f] < i - g)suff[i] = suff[i + m - 1 - f];else {if (i < g)g = i;f = i;while (g >= 0 && x[g] == x[g + m - 1 - f])--g;suff[i] = f - g;}}}void preBmGs(char *x, int m, int bmGs[]) {int i, j, suff[XSIZE];suffixes(x, m, suff);for (i = 0; i < m; ++i)bmGs[i] = m;j = 0;for (i = m - 1;